JP2010212241A - Secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary battery for stably connecting an electrode assembly and a terminal. <P>SOLUTION: The secondary battery includes the electrode assembly containing a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode, a case formed with a space where the electrode assembly is embedded, a cap plate connected to the case, the terminal electrically connected with the electrode assembly and exposed outside, and a current collector formed with a support projection electrically connecting the electrode assembly and the terminal and inserted into the electrode assembly, and a welding projection in contact with the side end of the electrode assembly. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a secondary battery, and more particularly to a secondary battery having an improved current collector structure.

  A rechargeable battery is a battery that can be charged and discharged, unlike a primary battery that cannot be charged. Low-capacity secondary batteries are used in portable electronic devices such as mobile phones, notebook computers, and camcorders, and large-capacity secondary batteries are widely used as power sources for driving motors in hybrid vehicles.

  Recently, a high-power secondary battery using a non-aqueous electrolyte with a high energy density has been developed. The high-power secondary battery is used for driving a motor that requires a large amount of power, for example, an electric vehicle. A plurality of secondary batteries are connected in series so that they can be used to form a large capacity secondary battery.

  One large-capacity secondary battery is usually composed of a plurality of secondary batteries connected in series, and the secondary battery is formed in a cylindrical shape, a rectangular shape, or the like.

  A prismatic secondary battery has an electrode assembly in which a positive electrode and a negative electrode are located with a separator interposed therebetween, a case in which a space in which the electrode assembly is incorporated is formed, and a terminal hole in which the terminal is inserted by sealing the case. The cap plate is electrically connected to the electrode assembly, and includes a terminal inserted into the terminal hole and protruding outside the case.

  In a conventional prismatic secondary battery, a lead tap that electrically connects an electrode assembly and a terminal is fixed to a side surface of a plain portion by ultrasonic welding. However, when the lead tap is welded to the side surface of the plain portion, the plain portion needs to have a certain length, and thus there is a problem that an unnecessary volume of the electrode assembly increases.

  In addition, since the ultrasonic wave must be transmitted to the plain portion through the lead tap, the thickness of the lead tap must be reduced. However, if the thickness of the lead tap is thin, there is a problem that the resistance of the lead tap is increased, and if the resistance is increased, there is a problem that a lot of heat is generated and the output is reduced.

  In addition, when an impact is applied to the secondary battery from the outside, there is a problem that a contact failure occurs between the lead tap and the electrode assembly. When the contact failure occurs, a lot of heat is generated inside and the output is reduced. There's a problem.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a new and improved secondary battery capable of stably connecting an electrode assembly and a terminal. Is to provide.

  In order to solve the above problems, according to an aspect of the present invention, an electrode assembly including a first electrode including an uncoated portion having an uncoated side and an uncoated end at an end thereof, and A weld that includes a first member that contacts the uncoated surface of the first electrode and a second member that contacts the uncoated end of the first electrode, and is attached to the uncoated end of the first electrode to the second member. A secondary battery including a current collector plate having a portion formed thereon is provided.

  An inner space may be formed in the electrode assembly, the first member may be a support protrusion, and the support protrusion may be located in the inner space. The height of the support protrusion may be substantially the same as the height of the internal space.

  The weld may be a weld projection. The welding protrusion may be formed in one shape selected from the group consisting of a triangle, a quadrangle, an arc shape, and a combination thereof. The welding projection may be welded to the plain end of the first electrode.

  The current collector plate has a first edge and a second edge, and the first member has a first side support extending at an angle with the first edge, and A second side support part extending at an angle with the second edge may be further included. The plain portion of the first electrode may be located between the side support portion and the support protrusion.

  The current collector plate may include an exhaust hole for exhausting a gas generated from the electrode assembly.

  A groove may be formed in the electrode assembly, and a height of the support protrusion may be substantially the same as a total height of the internal space and the groove. The current collector plate may further include an exhaust passage that extends in a direction opposite to the support protrusion from a position corresponding to the support protrusion.

  The secondary battery may include a case containing the electrode assembly, an electrode terminal electrically connected to the electrode assembly, and a cap plate coupled to the opening of the case. The current collector plate may be a first current collector plate, and the electrode assembly may further include a second electrode including a plain portion having a plain portion and a plain end at an end portion. The secondary battery includes a first member that contacts the ungrounded surface of the second electrode, and a second member that contacts the uncoated end of the second electrode, and the second member includes the second electrode. A second current collector plate having a weld portion attached to the plain end may be included. The case may be square.

  The cap plate includes a vent member. The current collector plate includes an exhaust hole, the first member of the current collector plate is a support protrusion, and the current collector plate includes an exhaust passage that extends in a direction opposite to the support protrusion from a position corresponding to the support protrusion. be able to. In the secondary battery, the vent member, the exhaust hole, and the exhaust passage may be configured such that gas generated from the electrode assembly is discharged to the vent member through the exhaust hole and the exhaust passage. .

  In order to solve the above problem, according to another aspect of the present invention, an electrode assembly including a first electrode having a first uncoated surface, a second ungrounded surface, and a uncoated end at an end, and the first A current collector plate including a first member that contacts at least one of the first and second non-ground surfaces, and a second member that is in contact with the non-ground end and has a welded portion attached to the non-ground end. A secondary battery is provided.

  An inner space is formed in the electrode assembly, and the first member includes a support protrusion that contacts the first ungrounded surface of the first electrode, and the current collector plate that contacts the second ungrounded surface of the first electrode. And a side support portion extending at an angle from the side surface. The electrode assembly may be fixed between the support protrusion and the side support portion.

  In order to solve the above problems, according to another aspect of the present invention, an internal space is formed including a first electrode, a second electrode, and a separator between the first electrode and the second electrode. An electrode assembly formed thereon, a support protrusion positioned in the internal space and having substantially the same height as the internal space, and a welding protrusion fixed to the plain end of the first electrode are formed, A secondary battery including a current collector in contact with the plain end of the first electrode is provided.

  The uncoated side is a portion of the uncoated portion substantially parallel to the flat surface of the electrode assembly, and the uncoated end is in a direction perpendicular to the flat surface of the electrode assembly, ie, It may be a plain part that faces the core axis direction of the electrode assembly.

  As described above, according to the present invention, the support protrusion is formed, and the lead member can stably support the electrode assembly, and is welded to the side end surface of the electrode assembly of the current collector plate, The volume of the part can be increased, thereby improving the output.

1 is a perspective view illustrating a rechargeable battery according to a first embodiment of the present invention. It is sectional drawing cut | disconnected and shown along the II-II line | wire of FIG. 1 is an exploded perspective view illustrating an electrode assembly and a current collector according to a first embodiment of the present invention. It is the perspective view which showed the current collecting plate by 2nd Embodiment of this invention. FIG. 6 is a perspective view showing a current collector plate and an electrode assembly according to a third embodiment of the present invention.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  FIG. 1 is a perspective view illustrating a rechargeable battery according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line II-II of FIG.

  Referring to FIGS. 1 and 2, the secondary battery 100 according to the first embodiment is an electrode assembly 10 wound up with a separator 13 as an insulator interposed between a positive electrode 11 and a negative electrode 12. including. The electrode assembly 10 is built in the case 34, the positive terminal 21 and the negative terminal 22 are electrically connected to the electrode assembly 10, and the cap plate 30 is coupled to the opening of the case 34. The secondary battery according to the first embodiment will be described by taking a lithium-ion secondary battery that is rectangular as an example.

  The positive electrode 11 and the negative electrode 12 include a coating portion that is a region in which an active material is applied to a current collector formed of a thin metal foil, and plain portions 11a and 12a that are regions in which no active material is applied.

  The positive electrode uncoated portion 11 a is formed at one end of the positive electrode 11 along the length direction of the positive electrode 11, and the negative electrode uncoated portion 12 a is formed at the other end of the negative electrode 12 along the length direction of the negative electrode 12. And the positive electrode 11 and the negative electrode 12 are wound up after interposing the separator 13 which is an insulator. The electrode assembly is pressed flat into a plate shape in a wound state, and a flat portion 18 and bent portions 19 disposed at both ends of the flat portion 18 are formed on the outer peripheral surface (see FIG. 3).

  The cap plate 30 is formed of a thin plate, and an electrolytic solution injection port (not shown) through which an electrolytic solution is injected is formed in the cap plate 30, and a sealing cap 38 is formed in the electrolytic solution injection port. Further, the cap plate 30 is provided with a vent member 39 having a groove formed so as to be broken by an increase in the set internal pressure of the case.

  An upper gasket 25 and a lower gasket 27 are interposed between the cap plate 30 and the terminals 21 and 22 to insulate the cap plate 30 and the terminals 21 and 22. A terminal in this specification is a concept including a positive terminal and a negative terminal.

  The lower gasket 27 is installed by being fitted into the terminal hole, and the upper gasket 25 is installed on the cap plate 30. A washer 24 for buffering the fastening force is installed on the upper gasket 25. The positive terminal 21 and the negative terminal 22 are provided with nuts 29 that support the terminals 21 and 22 at the top.

  A current collector plate 50 is attached to the positive electrode plain portion 11 a of the electrode assembly 10 by welding, and the current collector plate 50 is electrically connected to the positive electrode terminal 21 via the lead member 28. A current collecting plate 50 is attached to the negative electrode plain portion 12a by welding, and the current collecting plate 50 is electrically connected to the negative electrode terminal 22 via the lead member 28. An insulating member 26 is installed between the lead member 28 and the cap plate 30 for insulation therebetween. The lead member 28 includes a current collecting lead portion 28 b attached to the current collecting plate 50 and a terminal lead portion 28 a attached to the terminals 21 and 22.

  FIG. 3 is an exploded perspective view illustrating the electrode assembly and the current collector according to the first embodiment of the present invention.

  Referring to FIG. 3, the electrode assembly 10 according to the first embodiment is pressed flat in a plate shape in a wound state, and an inner space 14 having an inner surface separated is formed in the center.

  Each current collecting plate 50 includes a first member that contacts the side surface of the uncoated portion of each electrode. The first member may be a support protrusion 52 that is inserted into the internal space of the electrode assembly. Furthermore, each current collecting plate 50 includes a second member that comes into contact with the end of the uncoated portion of each electrode. The second member may be a welding protrusion 54 that is in close contact with the side end of the electrode assembly 10 and pressurizes the plain portions 11a and 12a.

  The support protrusion 52 is formed by being connected along the length direction of the current collector plate 50 at the center in the width direction of the current collector plate 50. The support protrusion 52 is formed by bending the current collecting plate 50, thereby forming a recessed groove on the back surface of the bulging and protruding portion. The height of the support protrusion 52 is a height corresponding to the height of the internal space 14 of the electrode assembly 10.

  The support protrusion 52 is inserted into the internal space 14 of the electrode assembly 10 and plays a role of supporting the electrode assembly 10, thereby causing poor contact between the electrode assembly 10 and the current collector plate 50 due to external impact. Can be reduced or prevented. The support protrusions 52 can support the electrode assembly 10 more stably by supporting the electrode assembly 10 not only in the length direction of the internal space but also in the width direction.

  Adhering plates 51 are connected and formed at both ends of the support protrusions 52, and the welding protrusions 54 are formed so as to be connected in the width direction of the attaching plates 51. The welding protrusion 54 is arranged so as to be connected in the direction in which the plain portions 11a and 12a are laminated, and can thereby contact the entire layer of the plain portions laminated. The welding projection 54 is formed by bending the adhering plate 51 into an arc shape, whereby a recessed groove is formed on the back surface of the bulging and protruding portion. However, the present invention is not limited to this, and the cross section of the welding protrusion 54 is formed of any one shape selected from a triangular shape, a square shape, an arc shape, and other appropriate shapes.

  The adhesion plate 51 is disposed in close contact with the side end surface of the electrode assembly 10, and the welding projection 54 presses and bends the plain portions 11 a and 12 a disposed on the side end surface of the electrode assembly 10. In the present specification, the side end surface refers to a surface perpendicular to an axis that becomes the center when winding.

  Thereby, the welding protrusion 54 and the plain parts 11a and 12a can contact in a relatively wide area. A plurality of welding protrusions 54 are arranged in the length direction of the current collector plate 50 and are attached to the side end face of the electrode assembly 10 by laser welding. If the welding protrusions are attached by laser welding in this way, the thickness of the current collector plate can be formed thicker than that by ultrasonic welding, thereby minimizing or reducing the resistance of the current collector plate. it can.

  Since the current collecting plate 50 is fixed to the side edges of the plain portions 11a and 12a, the areas of the plain portions 11a and 12a are relatively reduced, and the area of the coating portion to which the active material is applied is increased. The overall output of the assembly 10 can be improved.

  FIG. 4 is a perspective view showing a current collector plate according to a second embodiment of the present invention. Referring to FIG. 4, the current collector plate 60 according to the second embodiment includes a protrusion 62 that bulges from the center, an attachment plate 61 connected to both sides of the support protrusion 62, and side edges of the attachment plate 61. The side support part 63 connected with the plain parts 11a and 12a of the electrode assembly 10 is connected.

  The support protrusion 62 is formed to be connected along the length direction of the current collector plate 60 at the center of the current collector plate 60 in the width direction, and is inserted into the internal space of the electrode assembly 10 to support the electrode assembly 10. Play a role.

  A welding protrusion 64 that presses and bends the plain portions 11a and 12a is formed in the adhering plate 61 that is connected to both side ends of the support protrusion 62 in the width direction. The welding projections 64 are arranged so as to be connected in the direction in which the plain portions 11a and 12a are laminated, and can thereby be in contact with the entire layers of the plain portions 11a and 12a laminated. The welding protrusion 64 is formed by bending the adhesion plate 61 into a quadrangle, and thereby a recessed groove is formed on the back surface of the bulging and protruding portion.

  The welding protrusion 64 according to the present embodiment has a trapezoidal cross section, but the present invention is not limited to this, and the welding protrusion has various shapes such as a triangle, an arc shape, and a quadrangle.

  A side support 63 is formed at the side end of the attachment plate 61, and the side support 63 is inclined and bent from the attachment plate 61, and contacts the outermost surfaces of the plain portions 11a and 12a to gather the plain portions 11a and 12a densely. To play a role. That is, the one-side plain part is densely packed between the one-side side support part 63 and the support protrusion 62, and the other-side plain part is densely packed between the other side support part 63 and the support protrusion 62.

  Although the secondary battery according to the present embodiment is configured as a lithium-ion battery, the plain portions 11a and 12a of the lithium-ion battery are configured as thin films as compared with other types of batteries such as lithium-polymer batteries. The Moreover, although the thickness of the plain parts 11a and 12a is smaller than the thickness of the coating part with which the active material was apply | coated, it arrange | positions separately by the coating part, without being concentrated. Accordingly, it is not easy to attach the current collector plate 60 to the end portions of the plain portions 11a and 12a that are excessively thin. However, when the plain portions 11a and 12a are closely packed between the side surface support portion 63 and the support protrusion 62 as in this embodiment, the current collector plate 60 is easily welded to the end of the dense plain portions 11a and 12a. Can adhere.

  FIG. 5 is a perspective view illustrating a current collector plate and an electrode assembly according to a third embodiment of the present invention. Referring to FIG. 5, the current collector plate 70 according to the second embodiment is connected at the protrusion 72 that bulges from the center, the attachment plate 71 connected on both sides of the support protrusion 72, and the side edge of the attachment plate 71. Side support portions 73 that contact the plain portions 11a and 12a of the electrode assembly 10 are included.

  The support protrusion 72 is formed at the center in the width direction of the current collector plate 70, is formed along the length direction of the current collector plate 70, and is inserted into the internal space of the electrode assembly 10 to be inserted into the electrode assembly 10. Play a role to support.

  Adhering plates 71 are connected and formed on both side ends of the support protrusion 72, and welding protrusions 74 that press and bend the plain portions 11a and 12a are connected to the attaching plate 71 in the width direction. The welding projection 74 is formed by bending the adhering plate 71 into a triangle, whereby the welding projection 74 presses and bends the plain portions 11a and 12a at the corners of the triangle.

  When the welding protrusion 74 is formed in a triangular shape in this manner, the heat collecting can be concentrated on the corner portion of the triangle to easily weld the current collector plate and the plain portion, and the stress is concentrated on the sharp portion. The part can be easily bent in one direction.

  A side support 73 is formed at the side edge of the attachment plate 71, and the side support 73 is inclined and bent from the attachment plate 71, contacting the outermost surfaces of the plain portions 11a and 12a, and collecting the plain portions 11a and 12a together. To play a role.

  A groove 15 into which the protrusion 72 is inserted is formed at the upper end of the electrode assembly 10. The groove 15 is formed so as to connect the inner space and the outer surface of the electrode assembly 10, and is disposed at both side ends of the electrode assembly 10. Further, the support protrusion 72 is in contact with the lower end of the internal space, and the upper end is inserted into the groove 15.

  On the other hand, exhaust holes 75 are formed in the current collector plate 70, and the exhaust holes 75 are formed at the upper end and the lower end of the current collector plate 70, respectively, and are connected to the attachment plate 71 and the support protrusion 72. In addition, a recessed exhaust passage 76 is formed on the back surface of the support protrusion 72, and the exhaust passage 76 is formed through the groove 15 and connected to the upper end of the electrode assembly 10. Accordingly, the gas generated from the inside of the electrode assembly 10 can move to the upper portion of the case 34 through the exhaust hole 75 and the exhaust passage 76.

  When gas is generated inside the electrode assembly 10, the electrode assembly 10 swells and the charging and discharging efficiency decreases. However, when the exhaust hole 75 is formed as in this embodiment, the gas can be easily discharged. .

  Further, the gas discharged from the electrode assembly 10 moves to the upper part and transmits pressure to the upper part to operate at the timing when the vent member 39 is set. However, as in the present embodiment, the exhaust passage 76 is connected to the electrode assembly. When formed to be connected to the upper end of the three-dimensional object 10, the generated gas can be easily moved to the upper part of the case 34.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Secondary battery 10 Electrode assembly 11 Positive electrode 12 Negative electrode 13 Separator 14 Internal space 15 Groove 21 Positive electrode terminal 22 Negative electrode terminal 30 Cap plate 34 Case 50 Current collector plate 51 Adhering plate 52 Support projection 54 Weld projection 63 Side support portion 75 Exhaust hole 76 Exhaust passage

Claims (19)

An electrode assembly including a first electrode including a plain portion having a plain portion and a plain end at an end portion, a first member that contacts the non-ground portion of the first electrode, and a first member that contacts the plain end of the first electrode. A secondary battery comprising a current collector plate including two members, wherein the second member is formed with a welded portion attached to the plain end of the first electrode.   The secondary battery according to claim 1, wherein an inner space is formed in the electrode assembly, the first member is a support protrusion, and the support protrusion is located in the inner space.   The secondary battery according to claim 2, wherein a height of the support protrusion is substantially the same as a height of the internal space.   The secondary battery according to claim 1, wherein the welded portion is a welding protrusion.   5. The secondary battery according to claim 4, wherein the welding protrusion is formed of any one shape selected from the group consisting of a triangle, a quadrangle, an arc shape, and a combination thereof. 6.   The secondary battery according to claim 4, wherein the welding protrusion is welded to the plain end of the first electrode. The current collector plate is formed with a first edge and a second edge,
The first member further includes a first side surface support portion extending at an angle with the first edge, and a second side surface support portion extending at an angle with the second edge. The secondary battery according to claim 2, wherein:   The plain portion of the first electrode is located between the first side surface support portion and the support protrusion and between the second side surface support portion and the support protrusion. The secondary battery according to 7.   The secondary battery according to claim 1, wherein the current collector plate includes an exhaust hole for exhausting a gas generated from the electrode assembly.   The secondary of claim 2, wherein a groove is formed in the electrode assembly, and a height of the support protrusion is substantially equal to a total height of the inner space and the groove. battery.   The secondary battery according to claim 2, wherein the current collector plate further includes an exhaust passage from a position corresponding to the support protrusion to a direction opposite to the support protrusion. A case containing the electrode assembly;
An electrode terminal electrically connected to the electrode assembly; and a cap plate coupled to the opening of the case,
The current collector plate is a first current collector plate;
The electrode assembly further includes a second electrode including an uncoated portion having an uncoated surface and a uncoated end at an end portion,
A first member that contacts the uncoated surface of the second electrode and a second member that contacts the uncoated end of the second electrode are attached to the uncoated end of the second electrode on the second member. The secondary battery according to claim 1, further comprising a second current collector plate on which a weld is formed.   The secondary battery according to claim 12, wherein the case has a square shape.   The rechargeable battery of claim 12, wherein the cap plate includes a vent member. The current collector plate includes an exhaust hole;
The first member of the current collector plate is a support protrusion;
The current collector plate includes an exhaust passage that extends from a position corresponding to the support protrusion in a direction opposite to the support protrusion,
The vent member, the exhaust hole, and the exhaust passage are configured such that gas generated from the electrode assembly is discharged to the vent member through the exhaust hole and the exhaust passage. The secondary battery according to 14. An electrode assembly including a first electrode having a first unfinished surface, a second ungrounded surface, and a uncoated end at an end, and a first member that contacts at least one of the first ungrounded surface or the second ungrounded surface; A secondary battery comprising a current collector plate including a second member formed with a welded portion that contacts the plain end and is attached to the plain end. An internal space is formed in the electrode assembly,
The first member has a side surface extended at an angle from a support protrusion that contacts the first ungrounded surface of the first electrode and a side surface of the current collector plate that contacts the second ungrounded surface of the first electrode. The secondary battery according to claim 16, further comprising a support part.   The secondary battery of claim 17, wherein the electrode assembly is fixed between the support protrusion and the side support part. An electrode assembly including an inner space including a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode; and A support protrusion having substantially the same height as the internal space and a welding protrusion fixed to the uncoated end of the first electrode are formed, and includes a current collector that contacts the uncoated end of the first electrode. A secondary battery characterized by the above.

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